(1) Field of the Invention
This invention relates to agricultural sprayers, and more particularly to such sprayers that capture and recirculate unused spray fluid.
(2) Description of the Prior Art
Weeds are a problem in cultivated crops, especially when the weeds are interspersed with the cultivated plants.
Workers in the art have employed various methods of eliminating post-emergent weeds, e.g., hoeing or pulling by manual labor, manually spraying herbicides, or spraying the entire crop with herbicides from conventional spraying equipment. However, such methods are costly because of labor expenses or wasted fluid or because of damage to the cultivated plants.
One solution of these problems is embodied in THE RECOVERY SPRAYER, manufactured by Riverside Chemical Company, a subsidiary of Cook Industries, Memphis, Tenn. This equipment sprays the herbicide horizontally through spray nozzles aligned with an opening in a capture chamber. The fluid streams are positioned above the tops of the cultivated plants. Any weeds of greater height than the crop intercept the streams and are sprayed. Fluid not so intercepted enters the capture chamber opening, and is captured and returned to a sump at the bottom of the capture chamber. The fluid in the sump is returned to the main supply tank by an injector. The fluid discharge of a pump is divided, one stream which powers the injector and another stream which flows to the spray nozzles.
The prior art uses a "double loop" or divided flow system with the supply of fluid being within the main flow and loop. The fluid which has been sprayed is returned to the supply of fluid, thus contaminating the fresh supply of fluid in the supply tank with impurities contracted by the fluid during the spraying process, e.g., dust, bugs and pollen.
Also, the device requires two means of pumping fluid, one to pump fluid from the supply tank and another to move fluid from the sump back to the supply tank. As previously described, the injector is used to move the fluid from the sump. Basically, injectors are inefficient fluid movers and this injector is powered by the spray pump which necessitates a large pump. When the sump is sucked dry, air is sucked into the fluid lines, causing chemical "foaming".